January 2019: ADAM Audio Studio Pro SP-5

A surprising collaboration makes this debut headphone something truly special

Review by Mike Metlay

ADAM Audio’s speakers have become a mainstay of many studios, from world-class mastering facilities using enormous multidriver towers to small home rigs with compact 2-way designs that live happily on a desktop. Now ADAM has released its first headphone, the Studio Pro SP-5, and the obvious question is: does the company that popularized folded-ribbon tweeters and redefined an entire subsection of the monitor market, have the ability to do something similar for headphones?

My answer would be, “Yes—with a little help from their friends.” A closer look is now in order…

A truly off-center idea

The SP-5 was born out of a design and manufacturing collaboration with fellow German firm Ultrasone, whose headphones have been reviewed in these pages several times over the past two decades. The SP-5 is built around the core technology of Ultrasone headphones: S-LOGIC Plus, a seemingly simple design tweak that has truly remarkable effects on the listening experience.

The idea behind S-LOGIC Plus is straightforward. In normal headphones, audio from the drivers is aimed directly into the ear canal. At first blush, that seems quite logical—the sound has to get to your eardrums, right? Well, yes, but a direct path isn’t how we hear in nature.

Our perception of audio involves a fairly complicated interaction of sound waves with the mass of the skull and the shape of the pinna—the fleshy outer part of the ear—well before it gets to the eardrum and is decoded by the brain. This is how we localize sounds: we can tell if a sound source is to our left or right, in front of or behind us, above or below us. All of this information is lost if sound enters the ear canal directly.

In S-LOGIC Plus, the driver is placed near the bottom of the earcup, so sound fires against the earlobe and the lower part of the pinna rather than directly into the ear canal. This causes it to bounce around against the pinna and inside the earcup before entering the ear canal, creating a much more natural-seeming sound localization and a finely etched, distinctive stereo soundstage.

The SP-5 at a glance

This offset driver technology forms the center of the SP-5, which otherwise has a fairly familiar design and boasts specs that one would demand of any high-quality studio reference headphone. It’s a closed-back circumaural (over-the-ear) dynamic design sporting 40 mm gold-plated transducers with a stated 8 Hz–38 kHz frequency response. The headphone has a 70Ω impedance and a 95 dB/mW sensitivity, getting nicely loud with even the relatively low-power headphone amplifiers inside smartphones.

The SP-5 features hinged earcups that can swivel 90º forward or fold for compact transport, a generously padded headband, and a removable cable that connects to the left earcup via a twist-lock submini plug. Rather than supply a single cable with a miniplug-to-1/4” TRS adapter, the SP-5 comes with two different cables: a 3-meter coiled cable with 1/4” plug and a 1.2-meter straight cable with miniplug. The headphones and both cables are stored neatly in a rigid plastic zipper case.

The SP-5 at a listen

Having done a lot of Ultrasone reviews in the past, I had a pretty good idea of what to expect when I put on the SP-5 and started listening to my reference library, but knowing that didn’t stop the smile on my face. I’ve said this multiple times over the years and will say it again: Ultrasone headphones sound amazingly, seductively good. You put them on and you just want to play your tunes for hours and hours instead of getting work done… for sheer listening pleasure, they’re hard to beat without spending a lot more money.

This leads me to the two cautions I always deliver to prospective buyers of headphones like this. First, be aware that the overall pleasure of the listening experience can make you less cautious about detailed examination of your tracks. Details are there, but you have to remember to listen for them! Second, note that the stereo soundfield of S-LOGIC Plus headphones is unlike that of conventional phones, but is also unlike that of actually listening to speakers in a room—they don’t remove the need to check your mixes on speakers. If you keep those two cautions firmly in mind, then go ahead and joyously immerse yourself in the sound of these phones.

The first thing you’ll notice about the SP-5’s sound is the stereo image, which is wide and extremely detailed, more than you’d be used to on conventional phones. There is a clear left/right separation and a phantom center image that seems to float not in the center of your head but ever so slightly in front of you, making for very easy examination of individual sound sources in a mix. It’s startling at first, but as I said—seductive.

Bass on the SP-5 is a treat—extremely tight, with fast transient response and a deep enveloping bottom octave, unbelievable on grand piano and bass. The mids might seem a little bit scooped to someone used to a mid-forward rock headphone, and this can be exaggerated by the soundstaging, but guitars and vocals stand out with beautiful detail. And the highs are clear and sweet without being shrill or harsh, revealing the complex treble details of live instruments while tracking and of high-resolution sound files on playback.

The SP-5 has good isolation, making it practical in front of open mics and therefore equally at home in the tracking room and at the console. The headband fits tightly but comfortably, and fatigue over long listening sessions isn’t usually a problem at reasonable listening levels.

Oh, and speaking of reasonable listening levels and fatigue, the SP-5 offers another benefit that ADAM doesn’t mention, but which Ultrasone does in its headphone literature and which I’ve experienced many times before. I haven’t delved into the science behind this, but S-LOGIC Plus makes headphones seem louder than they actually are, by several dB. As a result, you can work at lower levels without sacrificing perceived punch, which leads to increased hearing safety and longer session times without potential harm. Cool!

Final thoughts

I’ll say it yet again: the SP-5’s listening experience won’t please every headphone user, but it delivers detail, wide and spacious soundstaging, and a fatigue-free listening experience even after hours of work. If that sounds like your cup of tea, then check out the Studio Pro SP-5… and thank those smart folks at ADAM Audio for bringing this amazing headphone technology to a wider audience in such a professional and elegant way.